Ab initio studies on hydrogen-bonded clusters. I. Linear and cyclic oligomers of hydrogen cyanide

Kofranek, Manfred; Karpfen, Alfred; Lischka, Hans

doi:10.1016/0301-0104(87)80219-7

Cited by 88 publications

(39 citation statements)

References 45 publications

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“…H) by about 0.12 and 0.06 A, respectively. Our estimated HF limit for this quantity, 2.34 A, agrees well with that found in [43]. Optimization of R(N .…”

Section: Resultssupporting

confidence: 84%

Cooperativity and electron correlation effects on hydrogen bonding in infinite systems

Suhai

1994

Int J of Quantum Chemistry

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Structural and electronic properties of hydrogen-bonded infinite chains of hydrogen cyanide and formamide molecules have been investigated by the ab initio crystal orbital method using several, partly highly polarized, atomic basis sets of increasing size at the Hartree-Fock (HF) level and by including electron correlation effects in the second order of Mller-Plesset perturbation theory. The results obtained show that hydrogen bonding in molecular crystals of the type investigated is a highly cooperative phenomenon, both from the structural and energetic points of view.Comparison with clusters of up to four monomers demonstrate how various structural parameters converge toward their limiting values in the infinite system. The results obtained for infinite HCN chains show an excellent agreement with those observed for solid HCN, whereas the infinite formamide chain proves to be a reasonable model for the corresponding liquid phase. 0

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“…H) by about 0.12 and 0.06 A, respectively. Our estimated HF limit for this quantity, 2.34 A, agrees well with that found in [43]. Optimization of R(N .…”

Section: Resultssupporting

confidence: 84%

Cooperativity and electron correlation effects on hydrogen bonding in infinite systems

Suhai

1994

Int J of Quantum Chemistry

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“…Concerning SCF results we will make frequent use of our previously published data on HCN clusters [43]. At the CPF level complete vibrational analysis within the framework of the harmonic approximation was performed for HCN and (HCN)2.…”

Section: Introductionmentioning

confidence: 99%

“…The trimer (HCN)3 has been dealt with in a frozen monomer approximation 1,37] applying a minimal basis set. Full geometry optimization and the calculation of vibrational spectra of the linear and cyclic trimer and of larger clusters have recently been carried out by us [43] at the SCF level applying extended basis sets. In addition, several ground state properties of the infinite, linear chain of hydrogen cyanide molecules have also been reported [41].…”

Section: Introductionmentioning

confidence: 99%

Ab initiostudies on structure, vibrational spectra and infrared intensities of HCN, (HCN)₂and (HCN)₃

1987

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Equilibrium structure, harmonic force field and dipole moment derivatives of HCN and (HCN)2 were investigated with the aid of ab initio methods applying extended basis sets and including electron correlation at the CPF level. Vibrational spectra and infrared intensities of HCN, (HCN)2 and of several isotopically substituted species are reported. Using our previous SCF calculations on (HCN)3 as a starting point a more approximate treatment of correlation effects on structure, vibrational spectra and infrared intensities of (HCN)3 was carried out. For the linear trimer (HCN)3 we predict a structure with two nearly equal intermolecular distances in qualitative agreement with SCF results. Infrared intensities of individual modes change dramatically upon complex formation. Besides the expected increase in the intensity of C-H vibrations involved in hydrogen bonding, particularly strong intensity enhancements were observed for C--'--N vibrations in the dimer and trimer in agreement with experimental data by Maroncelli et al. and with the known CmN intensity in solid HCN.

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“…(3) and (6) shows the possibility of interpreting R as an order parameter not only within the approximation discussed before. This follows from the relation (8) which is always fulfilled for IR and UV spectroscopy. Therefore, R is an order parameter 3 with respect to the coordinate system ii resulting from x f by means of the transformation coefficients given by Eq.…”

Section: Theoretical Backgroundmentioning

confidence: 91%

“…Therefore, R is an order parameter 3 with respect to the coordinate system ii resulting from x f by means of the transformation coefficients given by Eq. (8). For CD spectroscopy, however,…”

Section: Theoretical Backgroundmentioning

confidence: 94%

The orientation axis comparison of order parameters of anthraquinone dyes in a liquid crystal phase

Kuball

Strauss

Kappus

et al. 1987

Ber Bunsenges Phys Chem

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Three different molecule-fixed coordinate systems have a distinct significance for the calculation of order parameters. Only one of them is suitable to define an orientation axis (xf) in order to obtain order parameters which can be used for a comparison between systems of different molecules. For the majority of point symmetry groups, these axes X: are fixed by symmetry. The selection of the orientation axis xf from the X: depends on a special quantitative condition. By means of 15 aminoanthraquinones dissolved in the compensated nematic phase of cholesteryl chloride/cholesteryl laurate and in addition some of them in ZLI 1695 (Merck), the consequences of the choice of the reference axis xj for determining order parameters have been analyzed. By this it has been shown experimentally that order parameters -measured by different methods IR, UV, e.g. -are only comparable if they refer to xf. For two dyes (4,12) the orientation axis xf switches about 4 2 depending on the special type of substituents. For the structure -order parameter relation it has been shown that the 15 dyes can be arranged in two series. One series obeys the usual rule of increasing S # with increasing length to width ratio.The second series does not fit in this dependence.

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Ab initio studies on hydrogen-bonded clusters. I. Linear and cyclic oligomers of hydrogen cyanide

Cited by 88 publications

References 45 publications

Cooperativity and electron correlation effects on hydrogen bonding in infinite systems

Cooperativity and electron correlation effects on hydrogen bonding in infinite systems

Ab initiostudies on structure, vibrational spectra and infrared intensities of HCN, (HCN)₂and (HCN)₃

The orientation axis comparison of order parameters of anthraquinone dyes in a liquid crystal phase

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Ab initio studies on hydrogen-bonded clusters. I. Linear and cyclic oligomers of hydrogen cyanide

Cited by 88 publications

References 45 publications

Cooperativity and electron correlation effects on hydrogen bonding in infinite systems

Cooperativity and electron correlation effects on hydrogen bonding in infinite systems

Ab initiostudies on structure, vibrational spectra and infrared intensities of HCN, (HCN)2and (HCN)3

The orientation axis comparison of order parameters of anthraquinone dyes in a liquid crystal phase

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Ab initiostudies on structure, vibrational spectra and infrared intensities of HCN, (HCN)₂and (HCN)₃